The concept of human emotion is recently demanded to be imbedded in industrial product and environment for enhancing quality of life. Human emotion is attempted to be qualified and quantified by physiological measurements. EEG variation, one of the physiological measurement, is observed to characterize psychological response in this study. This study is to find function and process of brain according to emotion. Twenty university students participated in this study and experienced positive and negative emotion by auditory stimulus. Delta, theta, alpha and beta waves showed characteristic variation in normalized sense according to positive and negative emotion. Local area showing significant difference between positive and negative emotion decreases with stimulus duration. Delta, theta and beta waves increase with negative emotion while alpha wave does with positive emotion.